In a conveyor chain coupling structure, a block link A has a connecting rod (2) provided at one of conveying-directional ends thereof to project in the conveying direction and a coupling bore (5) formed at the other conveying-directional end. A pair of toroidal bush bearings (25, 30) is provided and a spherical bush (2) to be fixed to the connecting rod (2) is provided between the pair of toroidal bush bearings (25, 30). The first toroidal bush bearing (25) is fitted slidably on a portion, at the side of the other conveying-directional end, of the spherical bush (20) while the second toroidal bush bearing (30) is fitted at the spherical concave surface (31) thereof slidably on a portion, at the side of the one conveying-directional end, of the spherical bush (20). Owing to this construction, the coupled parts will not rattle, which will thus cause no pulsation or noise but will assure a smooth relative oscillation or reciprocal relative rotation of the block links. Further, this conveyor chain coupling structure is simplified, robust and durable than ever, and can be assembled and disassembled easily even in a narrow space. Also, the maintenance and the like can be made easily. Such jobs will be completed in a reduced time. Thus, the coupling structure very easy to handle and can be designed highly compact. Further, since it is suitable for mass production with a reduced cost of manufacture and can implement an inexpensive conveyor chain.